U.S. patent application number 15/712174 was filed with the patent office on 2019-03-28 for tread for a tire.
The applicant listed for this patent is The Goodyear Tire & Rubber Company. Invention is credited to Peter Andre KINDT, Alexander OSSIPOV, Julien Alexandre VAISSAUD.
Application Number | 20190092101 15/712174 |
Document ID | / |
Family ID | 63592578 |
Filed Date | 2019-03-28 |
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United States Patent
Application |
20190092101 |
Kind Code |
A1 |
VAISSAUD; Julien Alexandre ;
et al. |
March 28, 2019 |
TREAD FOR A TIRE
Abstract
A tread for a tire includes a first circumferential groove
extending in a circumferential direction entirely encircling the
tire, the first circumferential groove having two sidewalls
extending radially outward from an annular base, each sidewall
defining a plane perpendicular to a rotational axis of the tire,
and a first groove rib projecting radially outward from the annular
base of the first circumferential groove, the first groove rib
extending circumferentially and entirely encircling the tire, the
first groove rib having two sidewalls extending radially outward
from the annular base of the first circumferential groove to a
radially outermost annular surface of the first groove rib, each
sidewall of the first groove rib defining a plane perpendicular to
a rotational axis of the tire, the sidewalls of the first
circumferential groove extending circumferentially and parallel to
the sidewalls of the first groove rib, the first groove rib having
a radial height less than a radial height of the first
circumferential groove.
Inventors: |
VAISSAUD; Julien Alexandre;
(Arlon, BE) ; KINDT; Peter Andre; (Arlon, BE)
; OSSIPOV; Alexander; (Leuven, BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Goodyear Tire & Rubber Company |
Akron |
OH |
US |
|
|
Family ID: |
63592578 |
Appl. No.: |
15/712174 |
Filed: |
September 22, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60C 2011/0355 20130101;
B60C 11/0302 20130101; B60C 11/047 20130101; B60C 2011/0341
20130101; B60C 2011/1361 20130101; B60C 11/13 20130101; B60C 11/042
20130101 |
International
Class: |
B60C 11/13 20060101
B60C011/13 |
Claims
1. A tread for a tire comprising: a first circumferential groove
extending in a circumferential direction entirely encircling the
tire, the first circumferential groove having two sidewalls
extending radially outward from an annular base, each sidewall
defining a plane perpendicular to a rotational axis of the tire;
and a first groove rib projecting radially outward from the annular
base of the first circumferential groove, the first groove rib
extending circumferentially and entirely encircling the tire, the
first groove rib having two sidewalls extending radially outward
from the annular base of the first circumferential groove to a
radially outermost annular surface of the first groove rib, each
sidewall of the first groove rib defining a plane perpendicular to
a rotational axis of the tire, the sidewalls of the first
circumferential groove extending circumferentially and parallel to
the sidewalls of the first groove rib, the first groove rib having
a radial height less than a radial height of the first
circumferential groove.
2. The tread as set forth in claim 1 wherein the radial height of
the first groove rib is one-half the radial height of the first
circumferential groove.
3. The tread as set forth in claim 1 further comprising: a second
circumferential groove extending in a circumferential direction
entirely encircling the tire, the second circumferential groove
having two sidewalls extending radially outward from an annular
base, each sidewall defining a plane perpendicular to a rotational
axis of the tire; and a second groove rib projecting radially
outward from the annular base of the second circumferential groove,
the second groove rib extending circumferentially and entirely
encircling the tire, the second groove rib having two sidewalls
extending radially outward from the annular base of the second
circumferential groove to a radially outermost annular surface of
the second groove rib, each sidewall of the second groove rib
defining a plane perpendicular to a rotational axis of the tire,
the sidewalls of the second circumferential groove extending
circumferentially and parallel to the sidewalls of the second
groove rib, the second groove rib having a radial height less than
a radial height of the second circumferential groove.
4. The tread as set forth in claim 3 further comprising: a third
circumferential groove extending in a circumferential direction
entirely encircling the tire, the third circumferential groove
having two sidewalls extending radially outward from an annular
base, each sidewall defining a plane perpendicular to a rotational
axis of the tire; and a third groove rib projecting radially
outward from the annular base of the third circumferential groove,
the third groove rib extending circumferentially and entirely
encircling the tire, the third groove rib having two sidewalls
extending radially outward from the annular base of the third
circumferential groove to a radially outermost annular surface of
the third groove rib, each sidewall of the third groove rib
defining a plane perpendicular to a rotational axis of the tire,
the sidewalls of the third circumferential groove extending
circumferentially and parallel to the sidewalls of the third groove
rib, the third groove rib having a radial height less than a radial
height of the third circumferential groove.
5. The tread as set forth in claim 4 further comprising: a fourth
circumferential groove extending in a circumferential direction
entirely encircling the tire, the fourth circumferential groove
having two sidewalls extending radially outward from an annular
base, each sidewall defining a plane perpendicular to a rotational
axis of the tire; and a fourth groove rib projecting radially
outward from the annular base of the fourth circumferential groove,
the fourth groove rib extending circumferentially and entirely
encircling the tire, the fourth groove rib having two sidewalls
extending radially outward from the annular base of the fourth
circumferential groove to a radially outermost annular surface of
the fourth groove rib, each sidewall of the fourth groove rib
defining a plane perpendicular to a rotational axis of the tire,
the sidewalls of the fourth circumferential groove extending
circumferentially and parallel to the sidewalls of the fourth
groove rib, the fourth groove rib having a radial height less than
a radial height of the fourth circumferential groove.
6. The tread as set forth in claim 5 wherein the sidewalls of each
of the first, second, third, and fourth groove ribs are parallel to
each other.
7. The tread as set forth in claim 5 wherein the sidewalls of each
of the first, second, third, and fourth circumferential grooves are
parallel to the sidewalls of the first groove rib.
8. The tread as set forth in claim 5 wherein each of the sidewalls
of the first circumferential groove is parallel to each of the
sidewalls of the second groove rib.
9. The tread as set forth in claim 5 wherein each of the sidewalls
of the second circumferential groove is parallel to each of the
sidewalls of the third groove rib.
10. The tread as set forth in claim 5 wherein each of the sidewalls
of the third circumferential groove is parallel to each of the
sidewalls of the fourth groove rib.
11. A method for reducing exterior noise of a tread under operating
conditions, the method comprising the steps of: projecting a first
groove rib radially outward from an annular base of a first
circumferential groove; extending the first groove rib
circumferentially to entirely encircle the tread; extending two
sidewalls of the first groove rib radially outward from the annular
base of the first circumferential groove to a radially outermost
annular surface of the first groove rib; and extending the
sidewalls of the first circumferential groove circumferentially and
parallel to the sidewalls of the first groove rib, the first groove
rib having a radial height less than a radial height of the first
circumferential groove.
12. The method as set forth in claim 11 wherein the radial height
of the first groove rib is one-half the radial height of the first
circumferential groove.
13. The method as set forth in claim 11 further comprising the
steps of: projecting a second groove rib radially outward from an
annular base of a second circumferential groove; extending the
second groove rib circumferentially to entirely encircle the tread;
extending two sidewalls of the second groove rib radially outward
from the annular base of the second circumferential groove to a
radially outermost annular surface of the second groove rib; and
extending the sidewalls of the second circumferential groove
circumferentially and parallel to the sidewalls of the second
groove rib.
14. The method as set forth in claim 13 wherein the sidewalls of
the first groove rib are parallel to the sidewalls of the second
groove rib.
15. The method as set forth in claim 13 wherein the sidewalls of
the first circumferential groove are parallel to the sidewalls of
the second groove rib.
16. The method as set forth in claim 13 wherein the sidewalls of
the second circumferential groove are parallel to the sidewalls of
the first groove rib.
17. The method as set forth in claim 13 wherein the sidewalls of
the first groove rib are parallel to the sidewalls of the second
groove rib.
18. The method as set forth in claim 11 wherein the annular base of
the first circumferential groove forms a cylinder concentric with a
cylinder formed by the radially outermost annular surface of the
first groove rib.
19. The method as set forth in claim 13 wherein the annular base of
the first circumferential groove forms a cylinder concentric with a
cylinder formed by the radially outermost annular surface of the
second groove rib.
20. The method as set forth in claim 13 wherein the annular base of
the second circumferential groove forms a cylinder concentric with
a cylinder formed by the radially outermost annular surface of the
first groove rib.
Description
FIELD OF INVENTION
[0001] The present invention relates to a pneumatic tire with an
improved tread, and more particularly, relates to a pneumatic tire
tread having improved acoustic characteristics.
BACKGROUND OF THE INVENTION
[0002] Conventionally, in addition to circumferential main grooves
and lateral grooves, pneumatic tire treads may have sipes on a
tread surface in order to demonstrate favorable functional
characteristics (e.g., low rolling resistance, good traction, good
durability, etc.).
DEFINITIONS
[0003] The following definitions are controlling for the disclosed
invention.
[0004] "Axial" and "Axially" means the lines or directions that are
parallel to the axis of rotation of the tire.
[0005] "Axially Inward" means in an axial direction toward the
equatorial plane.
[0006] "Axially Outward" means in an axial direction away from the
equatorial plane.
[0007] "Bead" or "Bead Core" generally means that part of the tire
comprising an annular tensile member of radially inner beads that
are associated with holding the tire to the rim.
[0008] "Belt Structures" or "Reinforcement Belts" or "Belt Package"
means at least two annular layers or plies of parallel cords, woven
or unwoven, underlying the tread, unanchored to the bead, and
having both left and right cord angles in the range from 18 degrees
to 30 degrees relative to the equatorial plane of the tire.
[0009] "Carcass" means the tire structure apart from the belt
structure, tread, undertread over the plies, but including the
beads.
[0010] "Circumferential" means circular lines or directions
extending along the perimeter of the surface of the annular tread
perpendicular to the axial direction; it can also refer to the
direction of the sets of adjacent circular curves whose radii
define the axial curvature of the tread, as viewed in cross
section.
[0011] "dBA" means A-weighted decibels, abbreviated dBA, or dBa, or
dB(a), which are an expression of the relative loudness of sounds
in air as perceived by the human ear. In the A-weighted system, the
decibel of sounds at low frequencies are reduced, compared with
unweighted decibels, in which no correction is made for audio
frequency. This correction is made because the human ear is less
sensitive at low audio frequencies, especially below 1000 hertz,
than at high audio frequencies.
[0012] "Directional Tread Pattern" means a tread pattern designed
for specific direction of rotation.
[0013] "Equatorial Plane" means the plane perpendicular to the
tire's axis of rotation and passing through the center of its
tread; or the plane containing the circumferential centerline of
the tread.
[0014] "Footprint" means the contact patch or area of contact of
the tire tread with a flat surface under normal load pressure and
speed conditions.
[0015] "Groove" means an elongated void area in a tread that may
extend circumferentially or laterally in the tread in a straight,
curved or zigzag manner. It is understood that all groove widths
are measured perpendicular to the centerline of the groove.
[0016] "Hertz" means number of cycles per second.
[0017] "Lateral" means a direction going from one sidewall of the
tire towards the other sidewall of the tire.
[0018] "Net to gross" means the ratio of the net ground contacting
tread surface to the gross area of the tread including the ground
contacting tread surface and void spaces comprising grooves,
notches and sipes.
[0019] "Notch" means a void area of limited length that may be used
to modify the variation of net to gross void area at the edges of
blocks.
[0020] "Ply" means a cord-reinforced layer of rubber coated
radially deployed or otherwise parallel cords.
[0021] "Radial" and "radially" mean directions radially toward or
away from the axis of rotation of the tire.
[0022] "Radial Ply Tire" means a belted or
circumferentially-restricted pneumatic tire in which at least one
ply has cords which extend from bead to bead are laid at cord
angles between 65 degrees and 90 degrees with respect to the
equatorial plane of the tire.
[0023] "Shoulder" means the upper portion of sidewall just below
the tread edge.
[0024] "Sidewall" means that portion of a tire between the tread
and the bead.
[0025] "Sipe" means a groove having a width in the range of 0.2% to
0.8% of the tread width. Sipes are typically formed by steel blades
having a 0.4 to 1.6 mm, inserted into a cast or machined mold.
[0026] "Tangential" and "Tangentially" refer to segments of
circular curves that intersect at a point through which can be
drawn a single line that is mutually tangential to both circular
segments.
[0027] "Tread" means the ground contacting portion of a tire.
[0028] "Tread width" (TW) means the greatest axial distance across
the tread, when measured (using a footprint of a tire,) laterally
from shoulder to shoulder edge, when mounted on the design rim and
subjected to a specified load and when inflated to a specified
inflation pressure for said load.
[0029] "Void Space" means areas of the tread surface comprising
grooves, notches and sipes.
SUMMARY OF THE INVENTION
[0030] A tread for a tire in accordance with the present invention
includes a first circumferential groove extending in a
circumferential direction entirely encircling the tire, the first
circumferential groove having two sidewalls extending radially
outward from an annular base, each sidewall defining a plane
perpendicular to a rotational axis of the tire, and a first groove
rib projecting radially outward from the annular base of the first
circumferential groove, the first groove rib extending
circumferentially and entirely encircling the tire, the first
groove rib having two sidewalls extending radially outward from the
annular base of the first circumferential groove to a radially
outermost annular surface of the first groove rib, each sidewall of
the first groove rib defining a plane perpendicular to a rotational
axis of the tire, the sidewalls of the first circumferential groove
extending circumferentially and parallel to the sidewalls of the
first groove rib, the first groove rib having a radial height less
than a radial height of the first circumferential groove.
[0031] According to another aspect of the tread, the radial height
of the first groove rib is one-half the radial height of the first
circumferential groove.
[0032] According to still another aspect of the tread, a second
circumferential groove extends in a circumferential direction
entirely encircling the tire, the second circumferential groove
having two sidewalls extending radially outward from an annular
base, each sidewall defining a plane perpendicular to a rotational
axis of the tire; and a second groove rib projects radially outward
from the annular base of the second circumferential groove, the
second groove rib extending circumferentially and entirely
encircling the tire, the second groove rib having two sidewalls
extending radially outward from the annular base of the second
circumferential groove to a radially outermost annular surface of
the second groove rib, each sidewall of the second groove rib
defining a plane perpendicular to a rotational axis of the tire,
the sidewalls of the second circumferential groove extending
circumferentially and parallel to the sidewalls of the second
groove rib, the second groove rib having a radial height less than
a radial height of the second circumferential groove.
[0033] According to yet another aspect of the tread, a third
circumferential groove extends in a circumferential direction
entirely encircling the tire, the third circumferential groove
having two sidewalls extending radially outward from an annular
base, each sidewall defining a plane perpendicular to a rotational
axis of the tire; and a third groove rib projects radially outward
from the annular base of the third circumferential groove, the
third groove rib extending circumferentially and entirely
encircling the tire, the third groove rib having two sidewalls
extending radially outward from the annular base of the third
circumferential groove to a radially outermost annular surface of
the third groove rib, each sidewall of the third groove rib
defining a plane perpendicular to a rotational axis of the tire,
the sidewalls of the third circumferential groove extending
circumferentially and parallel to the sidewalls of the third groove
rib, the third groove rib having a radial height less than a radial
height of the third circumferential groove.
[0034] According to still another aspect of the tread, a fourth
circumferential groove extends in a circumferential direction
entirely encircling the tire, the fourth circumferential groove
having two sidewalls extending radially outward from an annular
base, each sidewall defining a plane perpendicular to a rotational
axis of the tire; and a fourth groove rib projects radially outward
from the annular base of the fourth circumferential groove, the
fourth groove rib extending circumferentially and entirely
encircling the tire, the fourth groove rib having two sidewalls
extending radially outward from the annular base of the fourth
circumferential groove to a radially outermost annular surface of
the fourth groove rib, each sidewall of the fourth groove rib
defining a plane perpendicular to a rotational axis of the tire,
the sidewalls of the fourth circumferential groove extending
circumferentially and parallel to the sidewalls of the fourth
groove rib, the fourth groove rib having a radial height less than
a radial height of the fourth circumferential groove.
[0035] According to yet another aspect of the tread, the sidewalls
of each of the first, second, third, and fourth groove ribs are
parallel to each other.
[0036] According to still another aspect of the tread, the
sidewalls of each of the first, second, third, and fourth
circumferential grooves are parallel to the sidewalls of the first
groove rib.
[0037] According to yet another aspect of the tread, each of the
sidewalls of the first circumferential groove is parallel to each
of the sidewalls of the second groove rib.
[0038] According to still another aspect of the tread, each of the
sidewalls of the second circumferential groove is parallel to each
of the sidewalls of the third groove rib.
[0039] According to yet another aspect of the tread, each of the
sidewalls of the third circumferential groove is parallel to each
of the sidewalls of the fourth groove rib.
[0040] A method in accordance with the present invention reduces
exterior noise of a tread under operating conditions. The method
includes the steps of: projecting a first groove rib radially
outward from an annular base of a first circumferential groove;
extending the first groove rib circumferentially to entirely
encircle the tread; extending two sidewalls of the first groove rib
radially outward from the annular base of the first circumferential
groove to a radially outermost annular surface of the first groove
rib; and extending the sidewalls of the first circumferential
groove circumferentially and parallel to the sidewalls of the first
groove rib, the first groove rib having a radial height less than a
radial height of the first circumferential groove.
[0041] According to another aspect of the method, the radial height
of the first groove rib is one-half the radial height of the first
circumferential groove.
[0042] According to still another aspect of the method, the method
further includes the steps of: projecting a second groove rib
radially outward from an annular base of a second circumferential
groove; extending the second groove rib circumferentially to
entirely encircle the tread; extending two sidewalls of the second
groove rib radially outward from the annular base of the second
circumferential groove to a radially outermost annular surface of
the second groove rib; and extending the sidewalls of the second
circumferential groove circumferentially and parallel to the
sidewalls of the second groove rib.
[0043] According to yet another aspect of the method, the sidewalls
of the first groove rib are parallel to the sidewalls of the second
groove rib.
[0044] According to still another aspect of the method, the
sidewalls of the first circumferential groove are parallel to the
sidewalls of the second groove rib.
[0045] According to yet another aspect of the method, the sidewalls
of the second circumferential groove are parallel to the sidewalls
of the first groove rib.
[0046] According to still another aspect of the method, the
sidewalls of the first groove rib are parallel to the sidewalls of
the second groove rib.
[0047] According to yet another aspect of the method, the annular
base of the first circumferential groove forms a cylinder
concentric with a cylinder formed by the radially outermost annular
surface of the first groove rib.
[0048] According to still another aspect of the method, the annular
base of the first circumferential groove forms a cylinder
concentric with a cylinder formed by the radially outermost annular
surface of the second groove rib.
[0049] According to yet another aspect of the method, the annular
base of the second circumferential groove forms a cylinder
concentric with a cylinder formed by the radially outermost annular
surface of the first groove rib.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] The present invention will be more clearly understood by the
following description of some examples thereof, with reference to
the accompanying drawings, in which:
[0051] FIG. 1 is a schematic orthogonal front view of a pneumatic
tire having a tread in accordance with the present invention.
[0052] FIG. 2 is a schematic sectional view taken along line 2-2 in
FIG. 1.
[0053] FIG. 3 is a schematic graph demonstrating decreasing noise
with the ribs in accordance with the present invention.
[0054] FIG. 4 is another schematic graph demonstrating decreasing
noise with the ribs in accordance with the present invention.
DESCRIPTION OF EXAMPLES OF THE PRESENT INVENTION
[0055] As shown in FIGS. 1-3, a pneumatic tire 1 in accordance with
the present invention may include a tread 100 with a first main
circumferential groove 10, a second main circumferential groove 20,
a third main circumferential groove 30, and a fourth main
circumferential groove 40 all extending in a circumferential
direction C of the pneumatic tire forming the tread 100. Five land
portions, or ribs 110, 120, 130, 140, 150 may be formed by these
main circumferential grooves 10, 20, 30, 40. The main
circumferential grooves 10, 20, 30, 40 may have, for example, a
lateral width between 3.0 mm and 20.0 mm and an example radial
depth between 5.0 mm and 13.0 mm.
[0056] In accordance with the present invention, the first
circumferential groove 10 may have two sidewalls 12 extending
radially outward from an annular base 14. Each sidewall 12 may
thereby define a plane perpendicular to a rotational axis 5 of the
tire 1. Projecting radially outward from the base 14 of the groove
10 may be a rectangular groove rib 210. The groove rib 210 may have
two sidewalls 212 extending radially outward from the base 14 to a
radially outermost annular surface 214 of the groove rib. Each
sidewall 212 may thereby define a plane perpendicular to a
rotational axis 5 of the tire 1. The sidewalls 12 of the first
circumferential groove 10 may extend circumferentially and parallel
to the sidewalls 212 of the groove rib 210. The sidewalls 212 of
the groove rib 210 may have a radial height above the base 14 of
about one-half a radial height of the sidewalls 12 of the first
circumferential groove 10. Alternatively, the sidewalls 212 of the
groove rib 210 may have a maximum radial height between 2.5 mm and
4.0 mm, such as 1.6 mm. The radially outermost annular surface 214
of the first groove rib 210 may form a cylinder concentric with a
cylinder formed by the annular base 14 of the first circumferential
groove 10.
[0057] In accordance with the present invention, the second
circumferential groove 20 may have two sidewalls 22 extending
radially outward from an annular base 24. Each sidewall 22 may
thereby define a plane perpendicular to a rotational axis 5 of the
tire 1. Projecting radially outward from the base 24 of the groove
20 may be a rectangular groove rib 220. The groove rib 220 may have
two sidewalls 222 extending radially outward from the base 24 to a
radially outermost annular surface 224 of the groove rib. Each
sidewall 222 may thereby define a plane perpendicular to a
rotational axis 5 of the tire 1. The sidewalls 22 of the second
circumferential groove 20 may extend circumferentially and parallel
to the sidewalls 212, 222 of the groove ribs 210, 220. The
sidewalls 222 of the groove rib 220 may have a radial height above
the base 24 of about one-half a radial height of the sidewalls 22
of the second circumferential groove 20. Alternatively, the
sidewalls 222 of the groove rib 220 may have a maximum radial
height between 2.5 mm and 4.0 mm, such as 1.6 mm. The radially
outermost annular surface 224 of the second groove rib 220 may form
a cylinder concentric with the cylinders formed by the annular
bases 14, 24 of the first and second circumferential groove 10,
20.
[0058] In accordance with the present invention, the third
circumferential groove 30 may have two sidewalls 32 extending
radially outward from an annular base 34. Each sidewall 32 may
thereby define a plane perpendicular to a rotational axis 5 of the
tire 1. Projecting radially outward from the base 34 of the groove
30 may be a rectangular groove rib 230. The groove rib 230 may have
two sidewalls 232 extending radially outward from the base 34 to a
radially outermost annular surface 234 of the groove rib. Each
sidewall 232 may thereby define a plane perpendicular to a
rotational axis 5 of the tire 1. The sidewalls 32 of the third
circumferential groove 30 may extend circumferentially and parallel
to the sidewalls 212, 222, 232 of the groove ribs 210, 220, 230.
The sidewalls 232 of the groove rib 230 may have a radial height
above the base 34 of about one-half a radial height of the
sidewalls 32 of the third circumferential groove 30. Alternatively,
the sidewalls 232 of the groove rib 230 may have a maximum radial
height between 2.5 mm and 4.0 mm, such as 1.6 mm. The radially
outermost annular surface 234 of the third groove rib 230 may form
a cylinder concentric with the cylinders formed by the annular
bases 14, 24, 34 of the first, second, and third circumferential
grooves 10, 20, 30.
[0059] In accordance with the present invention, the fourth
circumferential groove 40 may have two sidewalls 42 extending
radially outward from an annular base 44. Each sidewall 42 may
thereby define a plane perpendicular to a rotational axis 5 of the
tire 1. Projecting radially outward from the base 44 of the groove
40 may be a rectangular groove rib 240. The groove rib 240 may have
two sidewalls 242 extending radially outward from the base 44 to a
radially outermost annular surface 244 of the groove rib. Each
sidewall 242 may thereby define a plane perpendicular to a
rotational axis 5 of the tire 1. The sidewalls 42 of the fourth
circumferential groove 40 may extend circumferentially and parallel
to the sidewalls 212, 222, 232, 242 of the groove ribs 210, 220,
230, 240. The sidewalls 242 of the groove rib 240 may have a radial
height above the base 44 of about one-half a radial height of the
sidewalls 42 of the fourth circumferential groove 40.
Alternatively, the sidewalls 242 of the groove rib 240 may have a
maximum radial height between 2.5 mm and 4.0 mm, such as 1.6 mm.
The radially outermost annular surface 244 of the fourth groove rib
240 may form a cylinder concentric with the cylinders formed by the
annular bases 14, 24, 34, 44 of the first, second, third, and
fourth circumferential grooves 10, 20, 30, 40.
[0060] The groove ribs 210, 220, 230, 240 may be disconnected from
the sidewalls 12, 22, 32, 42 of the circumferential grooves 10, 20,
30, 40 such that the groove ribs 210, 220, 230, 240 reduce exterior
noise under operating conditions of the tread 100 and tire 1 while
having minimal effect on other functional characteristics of the
tread and tire, such as cornering, braking, rolling resistance,
wear, etc. Advantageously, the groove ribs 210, 220, 230, 240 in
the circumferential grooves 10, 20, 30, 40 may not significantly
alter the structural behavior of the tread 100 and tire 1, other
than reduction of noise. FIGS. 3 & 4 show this noise reduction
through almost the entire test frequency range when adding the
groove ribs 210, 220, 230, 240 to a tread pattern, such as the
tread 100.
[0061] While the present invention has been described in connection
with what is considered the most practical example, it is to be
understood that the present invention is not to be limited to the
disclosed arrangements, but is intended to cover various
arrangements which are included within the spirit and scope of the
broadest possible interpretation of the appended claims so as to
encompass all possible modifications and equivalent
arrangements.
* * * * *